A liquid crystal display device such as a liquid crystal television requires a separate backlight device as an illumination device since the display panel, which is a liquid crystal panel, does not emit light on its own, for example. This type of backlight device is largely categorized into direct-lit and edge-lit, depending on the configuration thereof. In either the direct-lit or edge-lit backlight device, optical sheets that impart optical effects (such as to make light planar) on light emitted from the light source are provided on the display surface side.
In backlight devices provided with these types of optical sheets, if vibrations or the like cause the optical sheets to deviate in position, then the optical sheets may rub against laminated members such as the liquid crystal panel, which could damage these laminated members. As a countermeasure, in backlight devices having optical sheets, a holding member is sometimes provided to hold at least part of the edge of the optical sheets to a casing such as a chassis in order to prevent or suppress positional deviations of the optical sheets. An example of this type of holding member that holds the optical sheets in the backlight device is described in Patent Document 1, for example.